1. Field
Exemplary embodiments relate to an ultrasonic probe of an ultrasonic diagnosis apparatus configured to diagnose diseases.
2. Description of the Related Art
An ultrasonic diagnosis apparatus is an apparatus configured to radiate ultrasonic waves toward a target portion at an inside of a subject, and to obtain an image with respect to a cross section of a blood flow of a soft tissue by receiving reflected ultrasonic echo signals.
The ultrasonic diagnosis apparatus, when compared to other image diagnosis apparatuses such as an x-ray apparatus, a CT Scanner (Computerized Tomography Scanner), a MRI (Magnetic Resonance Image), and a nuclear diagnosis apparatus, is provided in a relatively small size and is generally less expensive, while being capable of displaying diagnostic images in real time. In addition, the level of safety of the ultrasonic diagnosis apparatus is relatively high, as no radiation exposure is present, and thus, as well as for gynecological diagnoses, the ultrasonic diagnosis apparatus is being widely used for diagnosis of hearts, abdomens, and urinary systems.
The ultrasonic diagnosis apparatus includes an ultrasonic probe configured to irradiate ultrasonic waves toward a subject so as to obtain images of an inside of the subject, and to obtain ultrasonic echo signals that are reflected from body parts of the subject.
In general, piezo-electric material, which is configured to generate ultrasonic waves by converting electrical energy into mechanical vibrational energy, is being widely used as a transducer that is configured to generate ultrasonic waves at the ultrasonic probe.
Recently, a cMUT (capacitive Micromachined Ultrasonic Transducer), a new-concept transducer, is being developed.
The cMUT, as a new-concept transducer configured to transmit and/or receive ultrasonic waves by use of vibrations of hundreds or thousands of micromachined thin films, is manufactured on the basis of the MEMS (Micro Electro Mechanical System) technology. After forming a lower electrode and an air gap at a board of a semiconductor being used in a general semiconductor process and then forming an air gap at an upper portion of an insulating layer having the lower electrode, when a thin film provided with a thickness of about several to thousands of angstroms as well as an upper electrode above the air gap, a capacitor is formed so as to be provided with the air gap therebetween.
When an alternating current is applied to the capacitor manufactured as described above, the thin films are vibrated, and ultrasonic waves are formed as a result. Conversely, in a case when the thin films are vibrated by outside ultrasonic waves, the capacitance of the capacitor is changed, and by detecting the change of the capacitance, the ultrasonic waves are received.
The cMUT as such is provided with a diameter thereof which is on the order of about tens of micrometers, and thus, even in a case when tens of thousands of the cMUTs are arranged, the size thereof may be only about several millimeters. In addition, through a single manufacturing process, tens of thousands of sensors may be able to be precisely and simultaneously arranged at desired positions, and since the cMUT element is connected to an ASIC as a result of a chip-bonding method, such as in flip-chip bonding, so as to apply electrical signals to the cMUT, the difficulty with respect to the degree of complexity of the process caused by conventional wirings may be solved.
The cMUT as such may be suitable for the manufacturing of 2D-array transducers, which is a recent trend, thereby contributing the development of multi-channel transducers.
When the number of transducer channels is low, the heat generated from electrical circuits provided as to drive a probe may be less than about 1 W, which is the level that may be naturally released through a probe case. However, as transducers are provided with multiple channels, the amount of heat generated therefrom may be increased up to the level of about 7 W, and therefore, the technological development to radiate and reduce heat from the ultrasonic probe is in demand.